The embodiments described herein relate generally to medical devices. More particularly, the embodiments described herein relate to systems and methods for phlebotomy through an intravenous catheter.
The typical hospitalized patient encounters a needle every time a doctor orders a lab test. The standard procedure for blood extraction involves using a metal needle (“butterfly needle”) to “stick” patients' veins in their arms or hands. Blood drawing is a manual, labor-intensive process, with the average patient requiring hours of direct skilled labor during a typical hospital stay. This needle stick is not only painful and a major source of patient dissatisfaction, but the nurses or specialized blood drawing personnel (phlebotomists) often have difficulty finding the vein in approximately 10-15% of patients, resulting in multiple, painful “stick” attempts. This results in significantly higher material and labor costs (needles and tubing must be disposed of after every attempt) and increased patient pain and bruising.
The current process for drawing blood is inefficient, taking on average 7-10 minutes, and more than 21 minutes for 10% of patients. These 10% of patients are referred to as Difficult Intra-Venous Access or more commonly as “tough stick” patients. If superficial veins are not readily apparent, blood can be forced into the vein by massaging the arm from wrist to elbow, tapping the site with the index and middle finger, applying a warm, damp washcloth to the site for 5 minutes, or by lowering the extremity over the bedside to allow the veins to fill. Each of these methods is time consuming and therefore costly.
Peripheral IV catheters (PIVs) are inserted into most patients while they are hospitalized and used for infusing fluids and medications. However, they are not designed for blood extractions. The failure rates for aspiration reach 20-50% when PIVs have been left inserted for more than a day. Blood extracted from PIVs is often hemolyzed, defined as the rupture of red blood cells and the release of their contents into surrounding fluid, resulting in a discarded sample and need to repeat the blood collection.
There are several mechanical barriers that can contribute to the shortcomings of extracting blood from a PIV. First, most catheters are formed from a soft bio-reactive polymer, the use of this material has led to a potential narrowing or collapse of the catheter as the negative pressure is applied for aspiration. Additionally, with longer indwelling times comes an increase in debris (e.g., fibrin/platelet clots) that build up on the tip of the catheter and within the lumen. This explains the relationship between failure rate and indwelling time. A third significant barrier is attributed to a “suction cup” effect, wherein the negative pressure created by aspiration through the catheter and the possible curved path of a vein result in the tip of the catheter adhering to the wall of the vein. As the negative pressure increases the vein can rupture resulting in “blowing the vein”, a major concern for phlebotomists during aspiration through a PIV.
Thus, a need exists for an improved system and method for phlebotomy.